Vibration-responsive device



C. R. MOORE VIBRATION RESPONSIVE DEVICE May 4 1926 2 Sheets-Sheet 1Filed March 1923 Mme/var Mame.

A My May 4 1926.

C. R. MOORE VIBRATION RESPDNSIVE DEVICE 2 Shee ts-Sfieet 7:

Filed March 2 1923 1/ Ian/11111101111010.

Patented ;May 4, 1926.

v UNITED STATES exams n. MOORE, or marnnwoon, NEW mnsnmassmnon 'rowns'rnnn morale comm, mconromrnn, or N W YORK, n. Y. a conrona'rron ornew 2on3.

, VIB BATION-RESPONSIVE DEVICE.

Application med larch 26, 1928. Serial No. 627,728

"To all whom it may concern:

Be it known that 1, CHARLES acitizen of the United States -,-Ma lewood,in the county oi lilssex, tats 81 of ew Jersey, have invented certainnew :and useful Improvements in Vibration-Reiponsive Devices, of whichthe following is i afull, clear, concise, and exact description. Thisinvention relates to mechanical c'oulfl-apli'ng devices, andmore-particularly relates to-coupling devices for acoustic vibrating asystems such as telephone transmitters, re-

izgg'ers, phonograph reproducers and the R. Moons, 'res1d1n at 15 Anobject of this invention-is to provide non-rigid elastic and dissipatingcoupling arrangement between a driving member and a driven memberwhereby the fnoving syswill transmit mechanical vibratory 20 energywithout appreciable resonance efiects.

'. further object is to provide an improved mounting for phonographreproducers' and the like.

This elastic coupling arrangement com- 2 prises in one form of thisinvention, thin sheets of metal foil or paper loosely packed between thedriving and driven elements'to adegree suflicient to provide such' adis- .wsipa on of the impressed'energy as to give 30 the of the couplingmeans is preferably secured from the thin layers of air containedbetween the foil sheets and for that reason the sheets need not be madeof heavy material,

38 and in general, foil light in weight such as aluminum foil will e'quite satisfactory.

With such an arrangement the dissipation u is due principally tothepressure on the i sheets causing the air between the sheets to be forcedout and in for each vibration. In employing such a coupling means to a.s '60 type of acoustic device, such as an e ectrie phonographreproducer, the phonograph needle by a suitable lever arm me be.attached-to a diaphragm or plunger w ich in turn is connected to theflexible wall :of a carbon chamber through the interm'ediary of a largenumber of the foil sheets packed between. When the needle is tra versinga sound record the mechanical vibrations of the lever arm will beconveyed to the carbon chamber by the compression and 7 expansion ofthe. foil sheets. Due to the qprsseuoe of theoll sheets. any resonance Qelect in the rep .w x will be substantially esired damping. Thedampingefi'ect reduced and the variations in the current flowing through thecarbon button will, therefore, be a more'faithful copy of the soundrecord. There will also be an a preciable reduction in the motion of thesi e wall of the carbon chamber as compared to the motion of the end ofthe needle stylus bar. Such a reduction is of considerable importance,since in general, it is unsatisfactory to fix rigidly the end of thestylus bar to the diaphragm or plunger which varies directly thepressure on the carbon granules due to the fact that the maximumpermissible motion of the plunger or diaphragm is much less thanitheusual motion of the stylus bar.

, Referring to the drawings:

Fig.1 represents this invention embodied in a telephone transmitter.

Fig. 2 is a modification of this invention in which the foil sheets aredisc sha d. v

- Fig. 3 isa modification in which t e foil packlng composes annularrings having openings of different sizes.

Fig. 4 is a modification in which the packing composes discs of varyingdiameters.

Fig. 5 discloses a form of this invention in which solid discsalternate'with annular rings to form the packing arrangement.

Figs. 6 and 7 represent this invention as applied to piezo-electriccrystals. Figs. 8 and 9 show an alternative arrangement for employingthis invention with piezo-ele ctric crystals.

Figs. 10 and 11 illustrate this invention in a phonograph reproducer.

Fig. 12 illustrates a push-pull phonograph reproducer employing thisinvention.

Referring more particularly to Fig. 1, a telephone transmitter isdisclosed therein comprising a carbon chamber 16 of the barrier buttontype, for example, as disclosed in my copending application Serial No.505,060, filed October 3, 1921. The carbon chamber comprising a circularplate or electrode 17 separated from the front electrode 18 by anannular ring 19 of insulating material which serves as a barrier betweenthe electrodes. A lead in wire 20 is con- V nected to the back electrode17 and a lead in wire 21 due ,to the metallic connection between themetallic case 22, and the metallic cup 23 is connected to the frontelectrode 18, so that, variations in the pressure exerted on the carbongranules may vary no the current flow in a suitable electric circuitconnected to leads 20 and 21. The bottom of the cup shaped member 23 iscovered with an insulating strip 27 which serves to insulate member 23from the electrode 17. The barrier 19 and electrode 17 are held in placeby the flange portion of the annular ring electrode 18 which is threadedwith the inner side of the casing 23.

The front of the carbon chamber is closed by a thin disc 24 ofinsulating'material, such as mica. Between the diaphragm 15 and theclosing disc 24 of the carbon chamber are a plurality of thin annularrings A plurality of similar thin annular rlngs 26 are 1ncluded betweenthe annular electrode 18 and the flexible wall 24 of the carbon chamber.The vibration of the diaphragm .15 due to the impressed sound waves, forexample, will be transmitted through the discs to the flexible wall 24of the carbon chamber there- 'by causing the pressure upon the carbon tobe varied in accordance with the impressed sound waves, and thevariation in the pressure on the carbon will produce variable electriccurrents in the circuit connected --to leads 20 and 21 in the well-knownmanner.

'It will be noted that the sole connection between the diaphragm and theflexible wall of the carbon chamber is through the intermediary of thethin annular rings 25 which are packed therebetwee n. These thin annu-'lar rings may bemade. for exampleyof paper or thin metallic foil havinga thickness as small as .001 .of an inch or less. Due to the fact thatthese thin sheets are loosely packed there will belocated thin films ofair between adjacent sheets so that when vibrations are impressed uponthe diaphragm 15 the air between the sheets will be forced in and outfor each complete vibration of the diaphragm. When the air is expelledin -this manner: the coupling between the diaphragm and the flexiblewall of the.

carbon chamber may 'be termed a resistance or frictional coupling. Forthe upper range ofspeechor music frequencies the resistance coupling issupplemented by what may be called an elastic coupling, due to thevibrations occurring rapidly enough that all of the air in the air filmsdoes not have suflicient time to escapebut is compressed and expandedinstead. Since the elastic coupling factor will increase with frequencyan efli cient reproduction ofthe tones or notes of high pitch will beinsured and these tones may often be over-emphasized if in some cases itis found desirable to do so. The resistance coupling due to theexpulsion of the air between adjacent sheets has been found to givesuflicient damping or dissipation of the impressed energy wherebyresonance effects in the moving system of the acoustic device maybesmoothed out or substantially eliminated." I

The thickness of the air film between adjacent sheets may vary withdifferent uses of this invention and a thickness of .00025 to .0005 in.has been found satisfactory in most instances. preferably should beslightly less-than the diameter of the. casing containing, a difierenceof the order of .01 generally being suflicient.

i It is particularly dcsirablegthat the foil sheets or rings should-lielight in weight so that their combined weight is negligible compared tothe mass .of the remainder of the movin system. The number ofsheets- Thediamcterof the sheets i employed between the diaphragm and the lflexible wall as well as their character and disposition rill dependupon the amount-of damping and kind of coupling, i. e. resistance orelastic, desired in any particular case, so that the particulararrangement disclosed-in Fig. 1 may be, modified to a substantial degreein other embodiments and uses of the coupling arrangement of thisinvention. In some cases an essentially resistance coupling may bedesired for example, while in other cases an essentially elasticcoupling may be preferred.

It is to be understood that the coupling means bet-ween the driving anddriven members may'comprise thin annular rings of uniform size or solidsheets or a combination of the two in any desired manner. For example,in Fig. 2 the driving and driven members 29 and 30 which are coupled todiaphragms or plungers 31 and 32 in a suitable housing 33 are coupled bya large number of thin but solid foil sheets 34. These diaphragms orplungers 31 and 32 are separated respectively from the end walls of thecasing 33 by thin foil annular rings 35 and A second modification isshown in Fig. 3 in which the driving and driven members 37 and 38 arecoupled by a large number of thin annular rings 39 having the openingsin the rings of varying diameters, whereby a cone-shaped air pocket isprovided between the two plung'crs'or diaphragms 40 and 41.

Such an air pocket between the driving and driven members may in somecases be of coupled by a plurality of thin sheets 47, some of which arediscs and others are annu- Jar rings. lf'the discs are alternated withthe annular rings. additional air ockets arc provaded'due to theopenings in t e annular rings being closed on either'side by one of Theair in the pockets will be the discs.

.drivin squeezed in and out as the vibrations of the member are beingimpressed upon tie driven member'46. 1

The coupling arrangement of this invention is also of considerableutility'in the our bodiment of piezo electric crystals for translatinmechanical vibrations into variations of e ectrical energy. As disclosedand claimed in the United States Patent No. 1,495,429 to AlexanderMacLean Nicolson dated May 27, 1924, subject piezophony, pres-' surevariations applied to a piezo-electric' crystal may be translated intovariations of electrical energy. One way in which the pressurevariations may be impressed upon the crystal is by means of the cou lingarran'gement of this invention as siown in 'Figslfi and 7. The crystal48 is rigidly attached at one end to a suitable support 49 and the otherend of the crystal is included between a large number of foil sheets 50enclosed in a suitable housing 51. This llOllS- ing 51 is rigidlyattached to a needle holder 52 which holds a' suitable needle 53 capableof undergoing vibrations due to its traversing a sound record 54 such asa phonograph record. The vibration of the needle 53 will therefore causethe housing 51 to vibrate'in a. plane at right an Ice to the plane ofthe drawing and this v1 ration through the in-, termedia-ry of the thinsheets 50 will exert corresponding variations in pressure upon thecrystal 48. These variations in ressure as disclosed in the abovementionet Nicolson patent will give rise to variable electromotiveforces which may be employed in any manner desired. y

The coupling between the needle holder and the crystal may also be madein the man- ,ner disclosed in Figs. 8 and!) in which one end of thecrystal 55 is held rigidly between a clamp 56. An extension of thisclamp comprises a hollow cylinder 57 along the axis of which is locatedthe needle holder 58 held in position solely by a spiral wrapping 59 ofa long sheet of thin metal foil or paper.

' The motion of the needle holder '58, due to the needle traversing asound record will be transmitted throughthe motion of the needle holder58, to cause variations in pressure exerted on the crystal 55 due to theintermediary of the damping action of the foil wraping 59. This couplingarrangement has en found to produce a faithful reproduction of the soundrecord in a much more satisfactory mannerthan if the needleholder.,were,r1gidly connected to the crystal due to the fact that the needleholder 58 of course must undergo an ap reciable vibratory motion while te crysta 55 should be subjected only to variations in pressure withoutap preciable motion being required.

Another modification of this invention is the lever arm of the .needleholder and the flexible wall of the carbon chamber is obtained by meansof the foil acking arrangement of this invention. barrier button carbonchamber isdisclosed having for its back electrode an annular ring 60separated from the front electrode 61 by an annular ring 62 ofinsulatingmaterial which constitutes the barrier as disclosed in myabove mentioned application. The carbon chamber is enclosed by a.flexible wall 63 of insulating material which isflexibly separated fromthe electrode 61 by a few annular sheets 64 of thin foil. The lever arm66 of the reproducer is connected at one end in a suitable manner to aneedle holder 64 and at the other end is rigidly connected to the centerof a diaphragm or plunger 67. Included between the plunger 67 and theflexible wall 63 of the carbon chamber is a packing of a plurality ofthin annular rings 68 which forms a' dissipating coupling between theplunger and the closure of the carbon chamber to give the desiredamount'of damping to the vibrations of the moving system of thereproducer. These rings 68 as described above may consist of aluminumfoil of a" cal energy and the resulting damping is dueprincipally to theair films between the various sheets of the packing and not due to theinertia of the packing. That is, the damping should be due principallyto the energy requiredto force out the air enclosed between the foilsheets. If desired, thin annular sheets 69 may be employed to provide aflexible separation between the plunger 67 and the closing member 70ofthe'reproducer.

, The above coupling arrangement between the flexible walllof the carbonchamber and the lever arm of the reproducer has been found to suppressto a very,substantial degreeany unnatural response of the reproducer forany frequency or band of frequencies which tends to be present inundesired amounts due to resonance effects of the moving system and theclosenessof the coupling can be made to vary with frequency andamplitude.

A modification of the arrangement of Fig. 11 is disclosed in Fig. 12 inwhich the invention is shown embodied in a carbon phonograph reproducerof the so-called push-pull type. The housing 70 includes a Ill) suitablecylindrical support 71, in each end of which is threaded a barrierbutton carbon chamber. Each carbon chamber comprises a back electrode 72 substantially hemispherical in form separated from the front electrode73 by the barrier 74 of insulating material. The flexible member 75 ofthe shown in Figs-'16 and 11 in which a carboncarbon .button isseparated from the front reprodu r sd s d electrode 73 by a few thinannular rings 76- to form a resilient packing. The lever arm -77 isconnected at one end in a suitable manner to a reproducing needle 78,while the other end of the lever arm is positioned between two dish orhat-shaped members 7 9 and 80 which are employed for communicating thevibrations of the sound record needle to each of the carbon chambers.The dishshaped member 80 is not rigidly connected to the flexible wall75 of the carbon chamber,

.but is connected thereto solely through the pending application,SerialNo. 505,059, filed October 3, 1921,. on vibration responsive aparatus.

n addition to damping the vibrations of the 'moving system of thereproducer the coupling arrangement 81 between the lever arm and theflexible wall of the carbon chamber also has the advantage that themotion of the end 84 of the lever aim does not cause the same amount ofmotion in moving the flexible wall of the carbon chamber, but theflexible wall 75 will undergo a maximum motion only a fractional part ofthe maximum motion of the end 8-1 of the lever arm, the fractionalamount being determined for any particular case by the number andarrangement of the packing of foil sheets. This reduction in the motionof the lever arm is of considerable advantage since the optimum motionfor the end 84 of the lever arm is greater than the permissible motionof the closing wall of the carbon chamber. 2

It will be apparent from the various disclosures made above that thisinvention may possess widely difierent embodiments and may be employedin a variety of ways for couplingv a driving and a driven member of anacoustic 'or other vibration responsive device without depart-ing in anyway from the spirit of this invention as defined in the appended claims.

The invention claimed; is:

ing a driving member, a driven member and an air-damped coupling meansbetween said members comprising a plurality of juxtaposed sheets of thinmaterialwith thin air films therebetween.

rality of loosely packed layers of thin flexible material arranged totransmit vibrations to said flexible member through the compression andseparation of said layers. I

3. A vibration responsive device comprising-a driving member, a drivenmember, and a coupling device between said members comprisin a pluralityof juxtaposed layers of thin exible material of a total mass smallcompared to the mass of the remainder of the moving system.

4. A vibration responsivedevice comprising a driving member, a drivenmember, and an air-damped coupling device between said members comprisinposed layers of t in metal foil loosely packed between said members andarranged vto transmit vibrationsfrom said driving member to said drivenmember throu h the compression and separation of said ayers.

v 5. A'vibration responsive device comprising a driving member adaptedto be vibrated by speech requency vibrations, a driven mem erand apluralit of thin metal foil sheets held between said members, thedistance between said members "being greater than the total thickness ofsaid sheets to provide airs aces between adjacentsheets.

. '6. A vi ation responsive device comprising a translating element, amovable member subjected to mechanical vibrations of speech frequencyand spaced from said element, and an air-damped cou ling means-betweensaid element and sai member'com rising a plurality 'of metal foil sheetsoosely packed between said element and said member, said sheets having acombined weight negligible compared to the weight oi the remainder ofthe'moving system.

In witness whereoffll hereunto subscribe my name this 20th day of MarchA. D., 1'923.

CHARLES R. MOORE.

a plurality of juxta- 4

